John Constable (1776–1837) depicted locks in over 60 paintings and drawings throughout his career. Before the advent of the railroad, locks, sluices, and the navigable, or un-navigable, state of the waterways were critical to anyone living or working alongside them. Deliberately calling attention to the importance to local commerce of maintaining and improving the lock system on the river Stour, Constable gave titles such as “Scene on a Navigable River” to landscapes depicting well-known towns in Suffolk. The range and development of Constable’s interest in the lock as a subject, which has not previously been addressed, is the subject of Thompson’s research. Her work will be important in preparing for an exhibition and catalogue on John Constable at the Philadelphia Museum of Art in 2008.